Field of the Invention
The disclosure generally relates to the valves. Specifically, the disclosure relates to the internally controlled speed of shifting of sub-plate mounted (SPM) valves.
Description of the Related Art
Sub-plate mounted (SPM) valves are used to control the direction of high pressure system fluid which in turn performs numerous functions on oil field equipment, such as in a lower marine riser package and a blowout preventer stack on an oil well. Current SPM valves are subject to high pressure differentials and flow rates which result in rapid, uncontrolled valve actuation rates. Typical SPM valves also have very rapid increases in flow areas and poor timing between the supply port and return port, which wastes fluid while the valve is shifting. This poor timing and high rate of actuation creates a fluid phenomenon known as “water-hammer,” which is a very high damaging pressure spike. This phenomenon can physically damage structures, operating equipment, hardware, valves, tubing and piping.
Valve timing and spool actuation speed control have been used previously for other applications such as directional control spool valves in off-highway equipment and machinery control. Usually the timing and actuation speed are used to control an external load at the end of a linkage or transmission clutch engagements. The actuation speeds are usually controlled using proportional solenoid valves and software control. Current sub-plate mounted (SPM) valves do not have any, or at least sufficient, bi-directional control of their actuation rates and fluid metering characteristics.
Increasing the shifting time of the SPM valve and controlling the area openings and timing will greatly reduce or eliminate the “water-hammer” effect and improve the efficiency of the fluid being supplied as well as make the overall system more robust and reliable. There remains then a need to provide a better system and method for controlling the shifting of valves.